Date: Tue, 3 Jun 2008 09:35:15 -0700
From: Greg KH <gregkh@suse.de>
To: Benjamin Thery <benjamin.thery@bull.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Eric Biederman <ebiederm@xmission.com>, Serge Hallyn <serue@us.ibm.com>,
       linux-kernel@vger.kernel.org, Tejun Heo <htejun@gmail.com>,
       Al Viro <viro@ftp.linux.org.uk>, Daniel Lezcano <dlezcano@fr.ibm.com>
Subject: Re: [PATCH 09/10] netns: Enable tagging for net_class directories
	in sysfs
Message-ID: <20080603163514.GB544@suse.de>
References: <20080602134438.224352910@theryb.frec.bull.fr> <20080602134439.782528644@theryb.frec.bull.fr> <20080603040818.GA18507@suse.de> <48456225.6070505@bull.net>
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On Tue, Jun 03, 2008 at 05:24:21PM +0200, Benjamin Thery wrote:
> Greg KH wrote:
>> On Mon, Jun 02, 2008 at 03:46:08PM +0200, Benjamin Thery wrote:
>>> net: Enable tagging for net_class directories in sysfs
>>>
>>> The problem.  Network devices show up in sysfs and with the network
>>> namespace active multiple devices with the same name can show up in
>>> the same directory, ouch!
>>>
>>> To avoid that problem and allow existing applications in network 
>>> namespaces
>>> to see the same interface that is currently presented in sysfs, this
>>> patch enables the tagging directory support in sysfs.
>>>
>>> By using the network namespace pointers as tags to separate out the
>>> the sysfs directory entries we ensure that we don't have conflicts
>>> in the directories and applications only see a limited set of
>>> the network devices.
>> I don't like it how the network subsystem is starting to leach into the
>> sysfs core here.  What happens when the next subsystem wants to do the
>> same thing?  And then the next one?  Will they all have to do this kind
>> of intrusive changes to sysfs?
> >
> > Can't this be done only in the network subsystem?
>
> I'm not sure to understand exactly what you mean.
>
> What you don't like is seeing these hunks of network code in
> fs/sysfs/mount.c? And you prefer to see these bits of code resides in
> the network subsystem instead and see only "generic" sysfs services in
> fs/sysfs/mount.c?

Yes, exactly.

I don't want the problem that if more subsystems want to implement
something like this, they too need to modify the sysfs core.

And the mess with the #ifdef, that's not nice either :)

> If this is it, I have some idea to implement a less intrusive
> sysfs_net_exit(), which can be shared with the other namespaces.
> Serge introduces the same kind of changes in patch 10 to fix an issue in  
> user namespace. I think we can share a bit of code and move the parts
> specific to each namespace in their own subsystems.

I think that would be a good idea.  Care to redo the series?

thanks,

greg k-h
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